How Do You Collect Samples From an Active Volcano?

How do you collect a fresh, uncontaminated lava sample hot from the volcano, then get it to the lab without it growing pesky crystals? Check out how researchers with the United States Geological Survey collect samples to monitor volcanoes in Hawaii!

Fresh lava smoothing out a pile of older volcanic rubble known as ʻaʻā.

Hawaii is a chain of volcanic islands, each producing gentle eruptions. While burps and gurgles from the craters can still produce nasty surprises, the low silica content means the basaltic lava flows are generally slow-moving and safe to approach with the proper training and precautions.


Hawaiian Volcano Observatory researcher collecting a sample from a fresh lava lake.

The technique is simple at heart: Dip a metal rock hammer into the flow, hooking a sample into a bucket of water to quench it. Quickly cooling the sample prevents the growth of any crystals, preserving the composition of the pāhoehoe lava. The sample is then sent to a local lab for quick analysis, then out to the mainland for a more in-depth analysis of the full chemical composition.


Volcanologist collecting lava sample by transferring it to a bucket of water with a rock hammer.

See for yourself in this researcher-eye-view video from a U.S. Geological Survey researcher in Hawaii:

Collecting samples is necessary for researchers at the Hawaiian Volcano Observatory to perform a chemical analysis of the lava. Basaltic lavas are low in silica, which makes them less viscous and less explosive than the higher silica content rhyolitic lavas. Regularly analyzing the lavas allows the researchers to monitor any changes in the magma plumbing system.


Never drip lava on your toes when collecting samples from a molten flow.

Approaching this close to an active volcano and its lava flows requires protective gear, but surprisingly less than you’d think. The key components are sturdy boots and pants, insulated gloves, long sleeves, a full-head heat-filter, and usually a sun-shading hat. The molten lava in the flow field usually has a temperature around 1,140 ºC (just under 2,100 ºF), which is hot enough to blister exposed skin.


Quickly quenching a lava sample in a bucket of water.

Once upon a time when I was a proto-scientist nudging into research, I studied volcanoes. But I only lasted three months in part due to a suddenly-hatched fear of death-by-lava when collecting some seemingly-crucial bit of data. If I lived near nice, happy volcanoes like Hawaii instead of the death-spewing hate-monster that is Mount Saint Helens, I, too, might be out in some tropical paradise jabbing a hook into a goopey pool of rock.


A lava-coated rock hammer is the best type of rock hammer.

[Hawaiian Volcano Observatory]

Image credits: USGS

Contact the author at or follow her at @MikaMcKinnon.


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